1. Field of the Invention
The disclosure relates to protecting and/or isolating heat sensitive components used in downhole applications.
2. Description of the Prior Art
Oil and gas are generally recovered from subterranean geological formations by means of oil wells. For the purposes of this disclosure, an oil well is a hole drilled through the Earth above such geological formations. Typically, the well is drilled to and more often through an oil producing formation. This hole is commonly referred to as a wellbore or bore hole of the oil well and any point within the wellbore is generally referred to as being downhole.
Wellbore temperatures can vary from ambient up to about 500° F. (260° C.) and pressures from atmospheric up to about 30,000 psi (206.8 mega pascals). Temperature and pressure conditions such as these can have an adverse effect on instruments used downhole. Heat especially can be undesirable for tools having electronic components. For example, wireline and/or Measurement While Drilling (MWD) logging tools for measuring certain formation characteristics and wellbore properties often use heat-sensitive electronic gauges and sensors. Elevated temperatures can restrict the amount of time that these wireline logging tools may be operated inside the wellbore, i.e., the temperature survival time. Generally speaking, exposure to excess heat can cause electronic components to work improperly or even fail.
Thus, there is a need for thermal isolation devices and methods that isolate downhole devices from the relatively high temperatures associated with subterranean wellbores and/or heat generated by downhole components.